1. Field of the Invention
The present invention is an apparatus for separating oil well products. More specifically, the invention is an atmospheric oil, water, solids, and gas separator designed for oilfield applications.
2. Description of the Related Art
Separators that are intended to separate oil, water, solids, and gas from a mixture, such as a mixture produced by an oil well, have been in use for years. One such separator was designed by the present inventor and is the subject of U.S. Pat. No. 5,073,266 which issued on Dec. 17, 1991 for an Apparatus for Separating Commingling Heavier and Lighter Immiscible Fluids. However, these separators have several problems or shortcomings.
One such problem is that most separators do not have any way to adjust the level or height of the oil-water interface within the separator tank in response to varying operational conditions. The level of the interface is critical to efficient separation. Separators that have means for adjusting the height of the oil-water interface do not have a good and easy way to adjust the location or level of the oil-water interface without shutting down the separator.
Another problem has been that most separators are not designed to handle large slugs of oil or water, and when the capacity of those separators has been exceeded during upset times, oil spills have occurred.
Still another problem with prior separators is that the inlet connection has not been at or near ground level which makes connecting the separator to the production well or other source of fluid to be separated much more difficult, time consuming, expensive, and most importantly, quite dangerous. Also any elevated connection is more difficult to service.
A further problem with prior separators has been that the concave side of the internal upper spreader has been oriented upward so that the spreader serves as a bowl for collecting solids. As this bowl fills, the solids tend to obstruct the inlets into the tank of the separator and shut off flow into the separator. Separation efficiency suffers. This finally results in the need to shut the unit down, drain it and clean out the solids from the top of the bowl shaped internal upper spreader.
Still a further problem with prior separators is that they re-entrain separated oil into the water layer due to disruption of the oil-water interface by the turbulence and slugs from the incoming fluid into the tank. Additionally, prior separators have proven to be less efficient as they tend to re-entrain otherwise separable oil in the water phase as a result of making separated oil droplets that are formed below where the incoming fluid enters the tank to rise up through the turbulent incoming water in order to reach the oil-water interface and the oil layer above the oil-water interface.
Still another problem with prior separators is that the flow within the tank does not promote sufficient retention time and does not slow down velocity of the flow sufficiently to allow the entrained oils to separate from the water.
A further problem with prior separators is that they do not have a degassing chamber or other means for allowing gas to separate from the mixture initially upon entering the separator to reduce the turbulence that the entrained gas causes as the mixture enters the separation section of the separator and the gas bubbles up through both the oil-water interface and the oil-gas interface before reaching the gas layer or section located at the top of the tank.
A final problem is that the water spillover weir and the oil spillover weir of prior separators are generally not engineered with sufficient capacity to accommodate extremely large loadings, surges, and slugs of water and oil, resulting in unit upset and oil spills
The present invention addresses all of these problems and shortcomings and provides several improvements over prior art separators.